<?php

$str = "This is 123 Hello World 456 in Php!";


while (preg_match("/(.*)123(.*)456(.*)/", $str, $matches)) {
  print_r($matches);exit;
  echo $search =  $matches[0];
  $str = str_replace($search,strtolower($search),$str);

}
echo "\n\n", $str,"\n\n";
